1. Field of the Invention
The present invention relates to an image processing apparatus capable of processing a plurality of command systems, and more particularly to an image processing apparatus suitable for use with a printer which prints out a plurality of data, each of which is described in a different page description language.
2. Related Background Art
In a conventional printer of this type, a first control program and a second control program, different from the first control program, are selectively used. The first control program is mounted fixedly on the printer main body. The second control program is stored in a storage medium which can be removably mounted on the printer main body.
The second control program is generated by emulating a command system (page description language) of another printer. Therefore, application programs of the other printer can be used by a host computer without modifying them.
In this manner, for example, a high quality command system of the first control program and a conventional command system of low quality can be used compatibly with each other.
In printing data of the second command system supported by the second control program, the host computer first sends a control program selecting command, and then sends data from the second command system to the printer.
However, since the printer is structured to removably mount a storage medium, it may occur that a storage medium storing a third control program supporting a third command system is mounted, and the third command system not supported by the host computer.
In such a case, since the third command system contains some part different from the command system of print data sent form the host computer, printing is disabled.